The National Drug Code is a unique ten-digit number and serves as a product identifier for human drugs in commercial distribution. The Food and Drug Administration (FDA) assigns the first five digits (known as the labeler code) and the registrant assigns the last five digits (known as the product and package codes).

The assignment of an NDC number does not denote approval of the product by the FDA. In fact, the assignment of an NDC number just represents the registration of a product for commercial distribution.

Each drug product is assigned a unique 10-digit, 3-segment number. The first segment, the labeler code, is assigned by the FDA. A labeler is any firm that manufactures the drug (including repackers or relabelers), or distributes the drug. The second segment, the product code, identifies a specific strength, dosage form, and formulation for a particular firm. The third segment, the package code, identifies package sizes and types. Both the product and package codes are assigned by the firm.

When companies manufacture drugs, the companies will print the NDC number on the drug contaniers such as box and bottle.

The NDC number will be in one of the following configurations: 4-4-2, 5-3-2, or 5-4-1
Example of a NDC with 4-4-2 configuration: 0172-5412-79
Example of a NDC with 5-3-2 configuration: 50383-824-16
Example of a NDC with 5-4-1 configuration: 51674-0116-1